The present invention relates to a padlock having a body portion and a shackle member lockable therein.
A padlock is known in the art, having a body portion whose one axial end is provided with a circular hole for accommodating a rotatable drum, and a plurality of blind holes extend inwardly from the circular hole. A drum is rotably received in the circular hole and has a plurality of through-going holes whose location and number correspond to those of the first-mentioned holes of the body portion. A spring, an inner pin, and an outer pin are located in a respective one of the through-going holes of the body portion and the drum. The outer pins have differring lengths. When a key having a plurality of projections of differing lengths is inserted into the drum so that the projections are inserted into the through-going holes of the drum, the outer pins move the inner pins against the force of the springs so that the proximal ends of the outer pins and inner pins coincide with an axial interface between the body portion and the drum. Thereby, the drum can rotate and engage or disengage a slot provided in one end section of the shackle member so that the latter can be locked in or unlocked from the body portion. The other end section of the shackle member is spring-biased in the body portion. Such a construction is disclosed, for example, in the Inventor's Certificate of the USSR No. 275 274. This construction has a disadvantage that its safety or "secrecy" is limited to combination of the holes of only one drum and the projections of only one key. Furthermore, the spring-biasing of the other end section of the shackle member is complicated. The known lock must have and actually has a cover which covers the drum from outside and holds it in connected condition with the body portion.